Diameter and shunt act as an alleviator of pulmonary hypertension: an echocardiography assessment of patients with ostium secundum atrial septal defect

Abstract

Abstract Background Ostium-secundum atrial septal defect (OS-ASD) increases pulmonary arterial systolic pressure (PSAP) and eventually leads to pulmonary hypertension (PH). Nevertheless, whether the characteristics of OS-ASD could serve as an alleviator within chronic-volume overload in the right atrium (RA) is unclear. Aims To evaluate a potential interaction of OS-ASD diameter and the shunt (Qp/Qs ratio) on PSAP values in patients with secondary PH. Methods We designed a cross-sectional study of 63 adult patients with OS-ASD. A conventional transthoracic echocardiography was performed using Vivid 9X-clear equipment (GE Vingmed Ultrasound, Horten, Norway) to evaluate the OS-ASD diameter and the Qp/Qs ratio. The PSAP was calculated by tricuspid regurgitation velocity with continuous-wave Doppler in the apical four-chamber view. Polynomic adjusted correlations were performed between the RA volume and the PSAP; we evaluated a double and triple interaction-effect of the OS-ASD diameter and Qp/Qs ratio, respectively adjusted for age, sex and body surface area. Results In our study population, 78% (n=49) were female, with a mean age of 41.8 (±15) years. 44% (n=28) with mild-PH, 38% (n=24) with moderate-PH and 17% (n=11) with severe-PH. Mean echocardiographic parameters were: RA volume 58.8 (±26.4) mL, PSAP of 55.9 (±20.7) mmHg, OS-ASD diameter 30.1 (±7.8) mm and Qp/Qs 2.9 (±0.9). We observed a cubic relationship between RA volume and PSAP (r=0.354, p=0.006; Figure 1A). ASD-Diameter had a negative interaction effect (β=−0.0231 95% CI: −0.043 to −0.003, p=0.03) of the relationship between RA volume and PSAP (Figure 1B). Furthermore, the addition of Qp/Qs ratio displayed a positive triple interaction effect (β=0.021 95% CI: 0.001–0.043, p=0.048) on the previously mentioned variables (Figure 1C) after adjusting for covariates. Conclusions The increase in OS-ASD diameter and shunt decreases PSAP values. Our results could indicate that OS-ASD could potentially ameliorate chronic-volume overload in patients with secondary PH. Funding Acknowledgement Type of funding sources: None. Figure 1